An attack on Save the Children's office in the eastern Afghan city of Jalalabad ended with at least two people killed and 20 wounded, an official said Wednesday.

"The fighting has ended. The security forces are clearing the building now," Attaullah Khogyani, a spokesman for the governor of Nangarhar province, told the French news agency AFP.

The four assailants — reportedly dressed as police — fired a rocket propelled grenade from a car outside the British charity's compound in the eastern city of Jalalabad.

They then clashed with security forces for about three hours, a provincial government spokesman said. Afghan TV news channels showed a plume of black smoke coming out of the compound and a vehicle on fire outside the office.

The Islamic State later Wednesday claimed responsibility for the attack. "A martyrdom-seeking operation with an explosive-laden vehicle and three immersing attacks targeted British and Swedish foundations and Afghan government institutes in the city of Jalalabad," ISIS said via its propaganda arm Amaq.

Jalalabad is the capital of Nangarhar province, on the border with Pakistan. The province has become a stronghold for ISIS.

The attack comes days after Taliban militants attacked the Hotel Intercontinental in the capital, Kabul, which killed at least 20 people, including 13 foreigners.

Red Cross 'drastically' reducing presence

The violence against Save the Children, which has been working in Afghanistan since 1976, is the latest in a number of assaults on foreign aid groups in the country.

The International Committee of the Red Cross and Red Crescent announced in October it would "drastically" reduce its presence in the country after seven workers were killed last year.

The decision by the charity highlighted the growing dangers for aid employees, who have increasingly become casualties of a surge in militant violence in recent years.

This article was originally posted on DW.com. Its content is separate from USA TODAY.